Safety brake mechanism



Dec. 22, 1953 w. E. BRADY 2,663596 SAFETY BRAKE MECHANISM Filed April 4, 1951 w 2 Sheets-Sheet 2 IN VEN TOR.

WM. E. BRADY TTORNEY Patented Dec. 22, 1953 UNITED STATES PATENT OFFICE i v i 2588598 1": i i

SFETY' BRAKE MEcHANrsM William E. Brady, ,Baldwim hiwa` Application Aprilfl, 1951, Serial No.V 219,250

4 Claims. (Cl. 303-84) I My present invention relates to means for SfiOpDing a car, truck, or any other machine, equipped with a hydraulic brake system, even though one of the pipes leading to the brakes of the front or rear Wheels should break and allow the hydraulic fiuid to escape. Another object of this invention is to provide means whereby the hydraulic fiuid may be replaced when it has leaked out of a wheel cylinder system so that the brakes work imperfectly.

In the drawings annexed hereto and forming a part hereof,

Fig. 1 is a plan view of the piping system of a car showing the pipes carrying the hydraulic fluid;

Fig. 2 shows an end view of the distributing cylinder;

Fig. 3 represents a longitudinal section substantially along the plane indicated by the vline 3- in Fig. 2;

Fig. 4 represents the same structure as Fig. 3 with parts vin a different operative position;

Fig. 5 represents a transverse section substantially along the plane indicated by the line 5-5 in Fig. 4, but with the valve in a position turned ninety degrees (90) to the left; i'

Fg. 6 represents a structure for turning the rotary valve member from inside of the vehicle; and

Fig. 7 represents a fragmentary cross-section along the plane indicated by the line 1-1, in Fg. 3. i

Reference will now be made in greater detail to the annexed drawingsfor a more complete description of this invention, which has been illustrated as applied to a four-wheel 'braking system, since those are predominating in theautomotive field, although, of course, it Will be understood that it can be applied to a two-wheel system or a system using more than four Wheels. We will assume that the front Wheels are denoted by the numeral I and the rear Wheels by the numeral 2. The distributing valve for the brake fluid is denoted by the numeral 3 and the master cylinder by the numeral 4. The pipes leading to the Wheels and 2 are denoted, respectively, by 5 and 6. The pipes leading from the distributing valve 3 to the pipes 5 and S are denoted by the numerals 1 and 8, respectively. The master cylinder 4 is connected to the distributing valve 3 by a pipe 9, and the piston of the master cylinder is operated by a piston rod 10. The brake pedal is indicated, generically, by the numeral l I. The cylinder of the brake valve is shown as having its ends closed by plates |2 and l3, and as having air bleeder members l4 and |5.

There are pistons |6 and l'l which are movable back and forth in the valve 3, and a stop member 18 for preventing'the pistons from going beyond the mld-point of the valve, as well as serving as a bleeder screw for a chamber 43. Gaskets |9 may be used betweenthe end plates |2 and 13 and the ends of the distributing valve 3 to prevent leaking of fluid; The pistons 16 and l'l have projections 5| reachingV toward the ends of the valve to keep the pistons from covering the openings from the pipes 1' and 8, the channels 20 and 2|, and the openings for the bleeder members l4 andV 15. These must be continuously kept open and the pistons'must, therefore, be kept away from them. c

The openings of the channels 20 and 2| are formed in the thick wall of the auxiliary block, or addition to the cylinder, and have angular extensions 23 and 24 extending through the lateralwall of the block. Other openings or channels 25, 26, and 21 extend through the wall of the auxiliary block or addition 28,' if same is used, and cooperate With a rotary valve member 29. A spring-pressed latching member 30 is located in the opening 25 and engagesin depressions in the face of the rotary valve member 29 to hold this in adjusted position and to keep it from moving out, longitudinally.

Rings 3| and 32 serve to prevent leakage between the rotary valve member 29 and the auxiliary block 28. In the member 29 is cut a circumferential groove 33 which receives fiuid from the master cylinder 4 through the pipe 9. An opening 34 opens into channel 35 and communicates through the latter with the pipe 9 which'leads to the master cylinder, and branch channels or angle extensions 23 and 24 lead from the channels 20 and 2| to the valve 29. Fluid pumped through the pipe 9 into the annular channel 33 may enter channel 36 through port 3'l'and, when the valve member 29 is turned to a position such that opening 36a is in alig'nment with channel 26, as shown in Fig. 7, fluid under pressure 'may flow from the angular extension 36athrough the passage 26 into the chamber 43 between the pistons IB and IT.

`When valve 29 is turned so that openings and 4| are in alignment with angular extensions 23 and` 24, fluid may pass the spring pressed ball 38 into channel 39. From channel 39, as shown in Fig. 4, the fiuid'may pass through openings 40 and 4| into theangular extensions 23 and 24 and channels 20 and 2| into the distributing valve 3,l Where it forces the pistons l6 and I'l back under pressure, as explained hereinafter. At the 3 same time, it will fill the pipes and 8 and the system connected therewith.

The opening in the valve chamber 43 is preferably cylindrical in shape but is eccentrically positioned in relation to the valve block, as shown in the upper part of Fig. 2. When the fluid pressure is built up in the valve chamber 43 by the pressure of the springs in` the brakes, the operator having relieved the pressure in the master cylinder-f=4,'1the: hydfaulic pressure in cylinder 43 "can be relieved by putting the valve member 29 in the position shown in Fig. 5, when the liquid flows out through openings 20 and 2| and the pipe 9. At the same time;=.liquidfis' discharged from chamber 43 through valve '42 and channel 21, there being no forward pressure in the pipe 9 and opening 3|.

Normally, the spring in the cylinder of each brake will force the fluid in the brake line back toward the master cylinder. However, if there isV a -break-in-1thesystemg' the-I pressure ten'ding to force the pistons' back'- will befins'ufficient Sto acccmplish this'whenfthe brake'is actuat'edi' into vbraking 'position,-the pistonfii, "as shown in Fig. 4 being in' actuated position' because offl'owe'red resistance. Ho'we'ver, pis'ten- 11 will be 'ableto exert partof' af'normall'breakingforce and get theffoperator' 'outf'of'fdifiiculty YBy turning' the rotary valve m'e'mberf29 tothe'positionshown in Fig; 4,:thepistons =|6^and will'be forced into non-a'ctuated position, shown-in'Fig. 3 by'the Springs of a wheel'rbra'ke. The fluid in chamber 43 will'be' relievedrthrough valve 42 and opening 35, therebeing no pressuref'in'pipe 9; as shown in Fig; 4. In Fig. 4, the passage 2B is cut 'off 'and the check 'valve 38fpr'events 'the :return of the fluid-from 'thefchamberfl to the'pipe9. Thus theA fluid'V pressure is' 'mainta-inedin the brake linesand' associated parts until 'any and' all of the bleeder members can befreinstalled or-closed.l After'that', the valve 29 maybe' returned tolits normal -operating position, -as shown-in Fig. '7. When res'toring fiuid'tothe brake lines; as the parts areas shown 'in Fig; 4,:the 'inward movementPof ther'pistonsf'i'and; isclim-ited by lugs m. i

-I-Iowever," when' the'zoperator 'i'eniov'es'V his' foot from the brake pedal, fluid infthe-'chamber 43, from having operatedthe brakes, will be allowed to'escape` from thechamber 43 whenthe pistons are forced back, 'there' 'being'no'pressure in the pipe 9,the spring icheck'42 yielding'under pressure of the fluid'in the chamber43 as'the pistons are retracted.

Therefis a break 'in thesection o'f'Fig. 3 so that' it is off-center, 'theopening 21 not intersecting 'the 'channel .20.1 Likewise, the channel or opening Risen-center and does not intersect the channel' 29. The' stopwmember `|8 'extends inwardl into' the'chamb'er 43 and eacts' as'means to prevent either pis'tonV` 8 v'or 1 `from interfering with 'the conveyance fof fluid" into the 'chamber 43. The stop member |8 'also'acts'as an'airbl'eeder'screw'to -let air' 'out 'of'the' chamb'er 43.

An indicatorf 44`is placed onfthe end'of the rotary valve member 29 to ndicate the position of the openings'in-'the'valve member. There is also aikn'ob 45 for the 'turingof the'valve member 29. Asv pointed out above, the springpressed valve member 38' is in an opening 39 in the rotary valve member '29. This opening 39 extends longitudinally of the rotary valve niember 29, and transverse openings 'extend from outside of this valve member 29 `to the opening Fig. 5, the openings in zthe' valve are as shown,

and there are open channels from the channel 34 through the openings 41 and 48, and from there through the outlets '49 and 59 to the angularextensions 23 and 24. This is for the purpose of permitting brake pressure without operation of the pistons IS and When pressure on the brakepedal relieved, the fluid will come back through pipes and 8, angular extensions 23 and 24,- `andV channels 49 and 58, 41 and 4B to channel 34 and the master cylinder 4.

Hiln'ffnormal braking position, the rotary valve member: 29fis'turned as shown in Fig. 3.- Here .the-fluid' cannot get out of the opening 39 but vmust gofthrough the circumferential groove l33, port 31, channel v33, channel 36a and opening 26 to ithe-chamber 43 where it can actuate pistons 'Il'and into braking position. Inithis position, the openings 40 and' '4| are down, as shown in Fig. 3,' but there'is no opening leading to the angular extensions 23 and? 24. Under -no circumst'ancesis there communication from channel 33 to Chamber 43 but there may be'communication'ifrom chamber 43` byway of valve 42 to channel 133, as when pistonsfl and Jil are moved toward the middle of valve 3.

When'the valve '29 is turned 'so that the arrow 4'4 points upwardly, the openings 49, 5B Vand-'41, 49 Aare horizontal, and openings 49, 4| are down, communicatingf with '34,1'and the openings- 38a communicates with the opening 25, and the pistons i6 and are pressed to the ends ofthe cylinder,l applying vthe brakes.

"Ifabreak occurs in the pipe '|,Val1owing the fluid to leak out, the piston IG will go' out until stoppedfby the projection 5| striking the end |3 of the valve 3, asshown in Fig.v 4. When the rotary valve member "29 is in the position shown in Fig. 3, 'there can be operation of the brakes by reasons of channels 35, 36, 36a and 26. However, when 'the valve'29 is turned until the arrow points `at 1, then the parts will be in the position shown in Fig. 4, and the piston will `be push'edtbackto starting. or neutral position, as shown in Fig.;.3,"whenithe` brake pedal is a'ctuated. The course 'of the'fluid under such ciroumstances is through pipe 9, circumferential groove`33, port 31, spring-pressed ball 38, channel VV39, openings 40 andV 4|; angular extensions 23 'and 24, Channels 2|Ir 'and 2|, into the 'valve chamber 22, thus pushing'the pistons IB and back. In order to limit the movement of the pistons IB and there are provided lugs Ela which engage the'stop member |8, thus furnishing meansffor stopping thetpistons. This looks the brakes until relieved by turning valve '29. On the other hand, if'the rotary valve member 29 is turned, as shown in' iFig. .5, and the master cylinder is actuated, the fluid will pass through openings 41 and 48, 49 and'tl, 23 and 24, 20 and 2| and return the pistons VHi and ll, putting on the brakes, Springs 52 plus the pressure of fluid in chambers 22 being in eXcess of the pressure of valve 42.

The structure shownin Fig. 6 is for the pur- 39. Two of these ;"openings 'are denoted as 4B pose' of actuating the rotaryV Vvalve ,member l29 from the driver's compartment. It is thought that it will be clear that the driver can operate the valve member 29 to cause operation of the brake as an emergency brake. If one of the pipes 'l and 8 should break, allowing the oil to escape from the braking system of the front or rear wheels, this would be regarded as an emergency. When the valve 29 is turned, as shown in Fig. 4, fluid pumped by a master cylinder will be pumped through openings 9, 35, 33, 'and 31 and pass valve 38 and through 40, 4|, 23, 24, 20, and 2! into chambers 22, thereby forcing the pistons toward the center of the cylinder body. When fiuid is pumped into circumferential groove 33, it cannot go through channel 21 because this is closed oif by valve 42. Continued pumping of the master cylinder will cause pressure to be built up in chambers 22 by reason of the fiuid forced through channels and 2|. This will cause pistons 16 and i? to be moved into contact with the stop IB, as shown by Il in Fig. 4. When the chambers 22 are filled withl fluid, there will be pressure built up in the tubes 'l and 8 to a point where the brake shoes will begin to contact the brake drums, causing braking action at the Wheels and, of course, this fluid will remain trapped as such until the valve 29 is turned, as in Fig. 5 to release this trapped fiuid which will release the brakes. A rod 53 is connected by a key to the valve member 29 in any suitable manner, as by bevel gearing or by a universal joint to head 55 which may be located in the driver's compartment. The head 55 is marked similarly to knob so the operator can see what he is doing.

It is of course understood that the specific description of structure set forth above may be departed from without departing from the spirit of this invention as disclosed in this specification and as defined by the appended claims.

Having now described my invention, I claim:

1. A safety brake mechanism which comprises a master cylinder and a pair of brake lines, a distributing cylinder adapted to communicate at its ends with said brake lines, a pair of pistons movable toward and away from each other in said distributing cylinder, means maintaining said pistons in spaced-apart relation, stop means limiting movement of said pistons, a conduit leading from said master cylinder, a valve cylinder between said conduit and said distributing cylinder, a first pair of ports leading from the end portions of said distributing cylinder to said valve cylinder, a first port leading from said valve cylinder to the approximately central portion of said distributing cylinder, between said pistons therein, a second port leading from the central portion of said distributing cylinder to said valve cylinder, a first check valve normally closing said second port to the fiow of fiuid toward said distributing cylinder, Springs acting between the end portions of said distributing cylinder and said pistons, and a rotary Valve positioned in said valve cylinder and movable between a first and a second position, said valve cylinder including a third port communicating with the first port in the first position of said rotary valve, whereby fiuid from said master cylinder may flow to the central portion of said distributing cylinder, thereby forcing said pistons outwardly and forcing fiuid into said brake lines, said rotary valve having, also, a second pair of ports communicating in the second position of said rotary valve with said first pair of ports, a second check Valve controlling said second pair of ports, and

' a third port communicating between said master sure in the space between said pistons, created by the action of the associated Springs and the pressure in the brake lines.

2. A safety brake mechanism as defined by claim 1 in which the second check valve is incorporated in said second port leading to the outer ends of said distributing cylinder so that fluid is retained under pressure in the brake lines until said rotary valve is moved out of said second position.

3. A safety brake mechanism as defined by claim 2 having an additional port establishing communication, in a third position of said valve, between the master cylinder and the outer ends of said distributing cylinder, and by-passing said third port and said second check valve associated therewith.

4. A safety brake mechanism which comprises a master cylinder and a pair of brake lines, a distributing cylinder adapted to communicate at its ends with said brake lines, a pair of pistons movable toward and away from each other in said distributing cylinder, means maintaining said pistons in spaced-apart relation, stop means limiting movements of said pistons, a conduit leading from said master cylinder, a valve cylinder between said conduit, and said distributing cylinder, a pair of ports leading from the end portions of said distributing cylinder to said valve cylinder, a first port leading from said valve cylinder to the approximately central portion of said distributing cylinder, between said pistons therein, a second port leading from the central portion of said distributing cylinder, a check valve in said second port, Springs acting between the end portions of said distributing cylinder and said pistons, a rotary valve positioned in said valve cylinder and movable between two positions, said valve cylinder including a port communicating with the port leading from the rotary valve to the distributing cylinder, in one position of said rotary valve, whereby fiuid from said master cylinder may flow to the central portion of said distributing cylinder, thereby forcing said pistons outwardly and forcing fiuid into said brake lines, said rotary valve having, also, a third port communicating in the second position of said valve with said pair of ports, a check valve controlling said third port, and a fourth port communicating between said master cylinder and said third port, in at least the second position of said master valve, whereby fiuid may be directed to the outer ends of said distributing cylinder and force one of said pistons toward the other, fiuid between said pistons fio-wing through said check valve by virtue of the superior pressure in the space between said pistons created by thel action of the associated Springs and the brake sprmgs.

WILLIAM E. BRADY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name l Date 2,053,557 Hess et al. Sept. 8, 1936 2.108,164 Cornwell Feb. 15, 1938 2,128,853 Roen Aug. 30, 1938 2.151.940 Rumsey Mar. 28,- 1939 

